Mg(II) and Zn(II) tetrathiafulvalene bicarboxylates with hydrogen-bond-assembled band-like supramolecular structures

Two coordination compounds, [Mg(HL)(phen)(H2O)3]·HL·phen (1) and [Zn2L2(phen)2(H2O)2] (2), with dimethylthio-tetrathiafulvalene-bicarboxylate ligand (L) have been prepared by temperature controlled solvothermal reaction. Crystal structure analysis revealed that compound 1 is a mononuclear octahedral complex with co-crystallized free ligands, while compound 2 is a dimer with two square pyramidal metal centers. Both the compounds show a 1-D band-like supramolecular structure assembled by hydrogen bonds. The hydrophilic carboxylate groups and water molecules are gathered at the centerline of the band, and the TTF moieties and phen molecules are arranged at the two sides. The molecules are further contacted through short S⋅⋅⋅S interaction forming a 2-D net. These metal-TTF-bicarboxylates are redox-active and can undergo two steps oxidization in solid state.